Refrigeration Cycle

Refrigeration Cycle:

REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser, the receiver drier, through the evaporator, and back to the compressor.
The refrigerant evaporation through the evaporator coil is controlled by an externally equalized expansion valve, located inside the evaporator case.

FREEZE PROTECTION
When the A/C is switched on, the compressor runs continuously, and the evaporator pressure is controlled by a Suction Throttle Valve (STV) to prevent freeze up.

REFRIGERANT SYSTEM PROTECTION
Dual-pressure Switch
The refrigerant system is protected against excessively high or low pressures by the dual-pressure switch, located on the receiver drier. If the system pressure rises above, or falls below the specifications, the dual-pressure switch opens to interrupt the compressor operation.

Fusible Plug
Open at temperature above 105°C (221°F), thereby discharging refrigerant to the atmosphere. If this plug is melted and opened, check the refrigerant line and replace receiver drier.

Pressure Relief Valve
The refrigerant system is also protected by a pressure relief valve, located on the end of high flexible hose near compressor. When the pressure of refrigerant in the system increases to an abnormal level [more than 3,727 kPa (38 kg/cm2, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the atmosphere.

Acceleration Cut System - Manual A/C:

ACCELERATION CUT SYSTEM
This system is controlled by the Electronic Concentrated Control System (ECCS) control unit. When the engine is heavily overloaded, the compressor is turned off for several seconds to reduce overloading.